1. Field of the Invention
The present invention relates to a spectacle plastic lens (particularly a spectacle plastic lens having high refractive index), a manufacturing method thereof, and a manufacturing method of a hard coat liquid.
2. Description of the Related Art
In recent years, many efforts have been made to develop a high refractive index plastic lens in order to reduce the thickness of spectacle plastic lenses. Although having many advantages such as lighter weight, better processability and higher impact resistance, the plastic lens is lower in hardness and therefore is inferior compared to a glass lens in terms of scratch resistance and weather resistance. For this reason, the plastic lens is generally covered with a hard film called “hard coat” especially when being used as spectacle lenses. In the case of the spectacle lenses, since an antireflection film is formed on the surface of the hard coat, hard coat material is required to have high refractive index, otherwise interference fringes will occur due to refractive index difference between the hard coat and the lens.
In order to obtain such a hard coat material having high refractive index, it is proposed that a metal oxide and an organosilicon compound (so-called silane coupling agent) are contained in the hard coat material. For example, Japanese Unexamined Patent Application Publication No. 2002-129102 (referred to as “Patent Document 1” hereinafter) discloses a coating composition containing an organosilicon compound (or a hydrolysate thereof) and sol of a composite oxide formed of titanium oxide, tin oxide and zirconium oxide. Such a coating composition has improved surface hardness, scratch resistance and wear resistance.
However, if an antireflection film is formed on the hard coat having high refractive index, impact resistance will decrease. To solve this problem, a technology is disclosed in Japanese Unexamined Patent Application Publication No. H09-136978 (referred to as “Patent Document 2” hereinafter), in which a primer layer is provided between the lens surface and the hard coat layer, so that both the high refractive index and high impact resistance can be achieved by suitably determining the material of the primer layer.